关键词: 光, 花青素, 转录因子, 转录调控, 园艺植物

Abstract:

Anthocyanins are among the most important flavonoid compounds in plants, which play significant roles in color formation of plant organ, such as flower and fruits, as well as antioxidant process. Light is one of the most important environmental factors affecting anthocyanin biosynthesis pathway, but it still remains unclear in the mechanism and signaling networks of light regulation of anthocyanin. This review briefly introduced the anthocyanin biosynthesis and transportation pathway, and summarized the molecular mechanism of anthocyanin transcriptional regulation by three kinds of transcription factors, including MYB, bHLH and WDR. In addition, it emphasized on the light signaling regulation of anthocyanin biosynthesis. The researches showed that the light environment (light intensity, light quality, and light duration) regulated the biosynthetic process of anthocyanin mainly through different light receptors (UVR8, CRYs, PHOTs, and PHYs), which affected the ubiquitination ability of COP1, the stability of HY5, and the stability of other light signal transcription factors, such as the phytochrome-interacting factors (PIFs). On the one hand, these light signal factors directly could bind to the promoters of MYB, bHLH and WDR, activate or inhibit these genes expression and then regulate the synthesis of anthocyanin. On the other hand, these light signal factors interacted with proteins of MYB, bHLH and WDR, affecting the stability of the MBW complex formed by them. In addition, these light signaling factors could also regulate anthocyanin synthesis through MBW independent pathways, such as HY5 also affect anthocyanin biosynthesis by regulating miR858. In addition, some unknown light signaling factors might directly or indirectly regulate anthocyanin synthesis genes and interacting with some vacuolar membranes proteins in a MBW independent manner, to change vacuolar acidification and regulate anthocyanin synthesis. At the same time, light signaling factors also affected some factors in the photosynthetic electron transport chain through MBW dependent or MBW independent pathways, then affected anthocyanin synthesis in plants. How these pathways were coordinated and which pathway was preferentially responded by light environments (light intensity, light quality, light duration)? This paper provided a basis to further investigate the molecular mechanism regulating anthocyanin biosynthesis by light signalings. The study explored the effective ways and target molecules for light regulation of anthocyanin accumulation, and created opportunities for the development of anthocyanin-rich horticultural crops through genetic and metabolic engineering, and light environmental management.

Key words: light, anthocyanins, transcription factor, transcriptional regulation, horticultural crops